﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Dome
{
    class Demo01
    {
        public static void Test1()
        { 
            Console.WriteLine("请输入圆的半径：");
            string r = Console.ReadLine();
            double radius = Convert.ToDouble(r);
            double area = 3.14 * radius * radius;
            Console.WriteLine(area);
        }
           
    }
}
